Conventional display systems particularly used for advertising purposes employ mechanical or electronic devices to facilitate the changing of the visual presentation of the advertisement item.
Attempts to provide a dynamic display system specifically for advertising purposes using an elevator cab as the primary driving means to allow a pliant display panel to be vertically displaced in upward and downward direction along a vertical path have been made as can be gleaned from the elevator display system shown in U.S. Pat. No. 4,677,779. Briefly, U.S. Pat. No. 4,677,779 features a display system comprising an elevator cab, an elevator shaft, a motor drive connected to the elevator shaft, and a display banner secured at the lower portion of the elevator cab. The display banner or panel is provided with display items printed on the surface portion thereof and its bottom end is wound about to a spring-loaded drum provided at the lower end portion of the elevator cab.
During the vertical movement of the elevator cab, the display banner of the aforementioned prior art tends to slack off or get loose primarily due to the wind load and the non-uniform accelerating and decelerating motion of the elevator cab. This technical problem tends to aggravate as the display banner is lifted at higher vertical distances. As the banner slacks off, the surface integrity thereof tends to distort and hence the visual distortion of the printed advertisement items or information in the banner which render the same unreadable.
The features of the prior art do not address the aforementioned technical problems of elevator display systems. Moreover, at higher vertical levels the wind load becomes higher and thus resulting in a more distorted and non-readable presentation of the printed contents of the display panel. This technical problem becomes more visible when the display panel is installed outdoor and allowed to be displaced vertically by a drive means such as a pulley and motor assembly in a manner substantially similar to the use of an elevator cab as the drive means as previously discussed.